CLC-4517 - Remove old and unused oauth logos

https://jira.ets.berkeley.edu/jira/browse/CLC-4517
Merge pull request #3194 from christianv/CLC-4517

CLC-4517 - Remove old and unused oauth logos
OEC-484, prod issue whereby GSI only course entries were not in students.csv
OEC-484, remove stray 'unless' condition left over from previous logic
OEC-484, only append records if ccn_set is non-empty
Merge branch 'OEC-484' of https://github.com/johncrossman/calcentral into OEC-484